Snaggletooth
SA's Morrelle Compasse
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Sailors Powerboat
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kimbottles
Super Anarchist
Russell Brown
Super Anarchist
Warm and fuzzies? Single outboard is still safer than flying in a single engine airplane. Have you ever had one quit?One outboard for the efficiency, two for the warm and fuzzies (depending on your playground and conditions you’ll be in)
kimbottles
Super Anarchist
Actually I have twice been in a small plane when the engine stopped. I am not a pilot. Both times the pilot managed to get the engine restarted.
Not nearly as concerning as sailing in a Force Ten Storm. The engines stopping was quite peaceful and quiet. The storm was LOUD!
Small planes glide fairly well, but fortunately we didn’t have to demonstrate that quality either time.
nige
Super Anarchist
I think I had about 90% of your reply correct in my mind when I wrote that
I LOVE the single engine and want to build a different version of the green tri at some point as the efficiency was so good and I learned so much about what did and didn't work. But When I'm out on a longer trip, in shitty conditions in Totoro, especially if I have the kids with me etc, it does make me feel better knowing I have two engines, two fuel tanks, batteries and fuel lines. I'd never had any failures with the 20's on the tri or Totoro at all. I have had two electrical (boat not outboard) and fuel supply issues since we put the 40's on Totoro- 600 hours ago - and have come home on one engine once, but its not something I expect or am concerned about. I'm not saying it would be the choice I'd make on another boat, just that if that is your priority, twins give you that... (more things = more potential problems too obviously
)Russell Brown
Super Anarchist
It just seems like so much more weight and expense and complexity to design for twin engines, not to mention the fuel burn. I'd rather carry a tiny "get home" motor. I'd like to know how Totoro handles with one engine kicked up.
I like what Aspen has done with their single engined asymmetrical power cats. I have seen one going by and was struck by how clean the wake was for a big power cat.
The photo is of the wake of my new 23 footer at 18 knots
I like what Aspen has done with their single engined asymmetrical power cats. I have seen one going by and was struck by how clean the wake was for a big power cat.
The photo is of the wake of my new 23 footer at 18 knots
kimbottles
Super Anarchist
fastyacht
Super Anarchist
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I had sketched up aa power outrigger as a concept 20 years ago. That really is a cool way to go. It gets the motor inline and better propulsive numbers with a larger screw and single engine.
However in the current paradigm, 2 engines is hardly "extra expense." The twin engine motorboat is a thing of the past Even the triple is becoming endangered. The Quad and the Quint are ascendent. There are even sextets in production. I've seen proposals for 4 Sevens at the stern That is 4 x 627 hp. Now the new Sevens will be over 1000 hp each.
kimbottles
Super Anarchist
That’s unfortunate and subject to diminishing returns (and is really silly).
As the very talented Paul Bieker has pointed out, the sweet spot for a planning motorboat is 16 knots +/-.
After crossing Puget Sound more than 7000 times during my commuting years in a variety of small motorboats, I came to believe that I had completely tested Paul’s theory and it held up very well.
And 16 knots +/- is smoother, quieter, more economical, easier to dodge floating obstacles, and just down right better (IMHO.)
As always, YMMV
(The biggest complaint I have for the Goetz 60’er is that they put too much HP aboard. My Tim Kernan designed 50’er (At 22,200#) is delightful at 16 knots +/- which leaves lots of reserve in my twin 200hp diesels.)
Of course I am way more laid back now that I am retired.
nige
Super Anarchist
I totally agree, its a trade off with high costs, but everyone has different uses and priorities (as shown in the wide array of "sailors power boats" in this thread). Steering like a tank, turning in its own length can be really nice too
I'm often taking 4-6 people on totoro (kids to soccer matches etc) which is a lot of weight and I do feel more comfortable with the extra HP/Twins in those scenarios, but I'm totally open to that being an irrational comfort. (fitting a single 60 or 80 would be a totally different problem to solve!)
I've played with one engine up on Totoro and it has an "efficient" mode of about 16kts at about 9nm/g but its not a great test unless I changed the props, they are far too large a pitch to reach higher RPMs on one engine. Its not worth it to test it with lower pitch props as you can't steer well anyway with the narrow engine wells. I agree though, the Aspens look great to me, especially if you actually built a light one. "my" boats have a bit of a different criteria though, I am going for speed first (in most sea states) while trying to get as much efficiency as possible. I'm not grown up enough to be comfortable going 16kts as they are actually commuters for appointments etc and I always seem to be in a hurry, so we generally aim for 24-26kts with as much efficiency as possible (5-6nm/g). The tri with the 20 (and foils) did about 13-14nm/g at 21kts, full throttle which I thought was amazing. It would have been significantly higher at 16kts but I never did long runs like that. Totoro with the 20's did about 7nm/g at 22-23kts, full throttle. I think the jump to the 40's would show significantly better numbers if we didn't have the wedged sterns. The tri with foil assist felt like such an efficient setup, with a single hull/engine being the only thing (other than the surface piercing foils) in the water - but its a tweaky boat and not for everyone for sure.
I do love your wake shot. Totoro is pretty compromised on that now when going slowly (having to put so much volume in the sterns to take the weight of the bigger outboards instead of changing the full lenght of the hull means it digs a hole when going slowly), its still very smooth at speed. I want to change the full hull shape again at some point but I think Brandon will kill me.
Couple of pics/videos of totoro's and the Tri's wake's just for fun
https://youtu.be/uI74BK8OXY4
And to the later posts, I cannot handle seeing these stacks of huge outboards on the back of boats. It makes no sense to me - so much leg drag and weight that has to be designed for all the way back there. I hope the fad passes soon!!
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Pertinacious Tom
Importunate Member
The link in my post goes to when the boat went from a single Tohatsu 9.8 to twins.
It really didn't make the boat go much faster, possibly because the builder told the designer to make it efficient at ten knots. He's a sailor and thinks (or thought) ten knots is pretty fast. He quickly started to develop a more powerboaty view of that speed. Even with twins, the throttles were often wide open or close to it. Then he learned that 20 hp Suzuki's don't weigh a whole lot more than the 9.8's and got a pair of those. Liked 'em so much he just replaced them with new ones. White this time. It's still not all that fast, possibly because 40 is not a lot of horsepower for any 27 foot power cat, especially one designed to go ten knots.
I drove the boat when it had one engine. It was pretty darn uncontrollable. Very little of it is in the water, not enough to create any kind of keel effect at all. Blows around like a leaf. Long enough at 27 feet that the single outboard back there didn't do much to turn it. It's a whole lot more controllable with twins, of course.
The single engine was attached to the middle of the transom, but without any motor well or anything at all in front of it. In steep chop, this resulted in ventilation on every wave. Fixable, but another problem with the single engine on this boat.
The owner likes the twins. If I knock off the other contenders and inherit it, it might go back to a single and get a trolling motor that doubles as a bow thruster.
Pertinacious Tom
Importunate Member
Yes, twice recently. The 150 Suzuki on my Twin Vee 22 just died when I shifted back to neutral after backing away from the boat ramp recently. I replaced all three of its fuel filters just to get people to stop telling me it's bad fuel and the problem persisted. A pro figured out it was something called an HPV valve or something. My brother said it stood for "high priced valve." $400 plus labor, so pretty accurate.
The 60 hp Tohonda on my 'toon boat overheats at cruising speed and shuts down. It will restart and will run indefinitely at idle without overheating. It got a whole new water pump assembly, shaft seals and everything. I didn't replace the thermostat but did steal my wife's candy thermometer and test it. It's fine. There are no clogs. Unlike the fuel system on the Suzuki, these haven't changed much since the 70's and 80's, when I used to more or less understand outboards. There's nothing wrong with the cooling system. It overheats. The pro's have it now.
Pertinacious Tom
Importunate Member
Depends on the boat. That's about the slowest my Twin Vee will plane. It likes to go 20 knots. It doesn't really like any other speed.
My 'toon boat will go 16 with the throttle wide open, but isn't happy. It seems to like to go 12, less in chop.
fastyacht
Super Anarchist
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kimbottles
Super Anarchist
Not much wake for a 22,200# 50’er at 25 knots. Even less at our normal 16 knots. (But Tim Kernan her designer is primarily a sailboat designer.)
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kimbottles
Super Anarchist
If I ever get around to building Bob’s 60’er with the single diesel it will be interesting to see her wake at 16 knots. 60x10.72 x 15,264#
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Veeger
Super Anarchist
Well Kim, when/if I get my 48’ powercat and you get Bob’s boat, we’ll have some interesting learnings given that they’ll both be about the same displacement…
fastyacht
Super Anarchist
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She will be in the transition or semiplaning regime at her max bow up trim but be8ng lean and light she wont trim all that much. Her chines will prbably remain wet unless you engage tabs.
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kimbottles
Super Anarchist
My Kernan motorboat does not seem to do any “bow up” running as she gets to planing, she just rises up level and we can see when we are on plane when her wake calms down. Narrow boats really like to slip through the water. (No tabs on the Kernan, and she doesn’t seem to need them.)
Next time you visit me we will give you a demo Fastyacht. (And the Mark T. Wendell Hu Kwa tea will be served again.)
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